Aerobic exercise is a popular form of exercise that improves one's cardiovascular health by reducing blood pressure and providing other benefits to the human body. Aerobic exercise generally involves low intensity physical exertion over a long duration of time. Typically, the human body can adequately supply enough oxygen to meet the body's demands at the intensity levels involved with aerobic exercise. Popular forms of aerobic exercise include running, jogging, swimming, and cycling, among others activities. In contrast, anaerobic exercise typically involves high intensity exercises over a short duration of time. Popular forms of anaerobic exercise include strength training and short distance running.
Many choose to perform aerobic exercises indoors, such as in a gym or their home. Often, a user will use an aerobic exercise machine to perform an aerobic workout indoors. One type of aerobic exercise machine is a treadmill, which is a machine that has a running deck attached to a support frame. The running deck can support the weight of a person using the machine. The running deck incorporates a conveyor belt that is driven by a motor. A user can run or walk in place on the conveyor belt by running or walking at the conveyor belt's speed. The speed and other operations of the treadmill are generally controlled through a control module that is also attached to the support frame and easily within reach of the user. The control module can include a display, buttons for increasing or decreasing a speed of the conveyor belt, controls for adjusting a tilt angle of the running deck, or other controls. Other popular exercise machines that allow a user to perform aerobic exercises indoors include elliptical trainers, rowing machines, stepper machines, and stationary bikes, to name a few.
One type of treadmill is disclosed in U.S. Pat. No. 7,575,537 issued to Joseph K. Ellis, et al. In this reference, an exercise treadmill is described as having an endless movable surface looped around rollers or pulleys to form an upper run and a lower run, the movable surface being rotated when one of the rollers or pulleys is rotated, and an exercise surface for walking or running while exercising, a weight resistance mechanism for providing a weight resistance for simulating the dragging or pulling of a load, wherein the weight resistance can be adjusted and set to a specific weight resistance setting; a movable hand controller operatively attached to the weight resistance mechanism for operating and controlling the exercise treadmill and the weight resistance mechanism. According to Ellis, the endless movable surface moves in a direction simulating walking or running backwards, and the weight resistance mechanism applies a constant and static force to the hand controller generally only in the same as the direction the endless movable surface moves and opposite a pulling direction. In this manner, according to Ellis, operation of the treadmill simulates the dragging or pulling of a load by a combination of the actuation of the weight resistance mechanism to simulate the load and the walking or running backwards to provide the dragging or pulling action. Other treadmills are described in U.S. Patent Publication Nos. 2007/0232463 issued to Yu Feng Wu and 2015/0352396 issued to William T. Dalebout.